A pledge to cut carbon emissions is less than it seems

At the G-8 summit in the Japanese resort town of Toyako, President George W. Bush proudly presented a pledge by the group's eight member nations to cut global greenhouse-gas emissions at least 50% by 2050. For a President who came into office publicly doubting climate change and has repeatedly refused to set specific limits on carbon emissions, the G-8 statement was a personal step forward.

Unfortunately for the rest of us, this year's G-8 summit—which marked the first time that leaders of the world's 16 biggest carbon emitters have sat down to talk about climate change—will be remembered as a lost...